1. Field of the Invention
This invention relates to a five-member auto-lock slider, for a slide fastener, composed of a slider body, a pull tab, a locking lever, a leaf spring and a cover, and more particularly to an auto-lock slider in which a leaf spring and a cover can be mounted in a stable form during the automatic assembling process of the slider.
2. Description of the Related Art
This type conventional auto-lock slide fastener slider is disclosed in Japanese Utility Model Laid-Open Publication No. Sho 58-100611. In this conventional auto-lock slider, as shown in FIG. 9, each of front and rear attachment lugs 113, 114 standing on the upper surface of an upper wing 106 of a slider body 101 has in its top surface a central recess 123, 123 in which each end of a leaf spring 104 is to be fitted. In assembling, the leaf spring 104 is placed over a locking lever 103 supported by the front and rear attachment lugs 113, 114, and then the leaf spring 104, the front and rear attachment lugs 113, 114 and part of the locking lever 103 on the upper wing 106 are covered by a cover 105 having on its inner wall surface a pair of projections (not shown) to be fitted in the respective recesses 123, 123 of the front and rear attachment lugs 113, 114.
FIG. 10 shows another conventional auto-lock slider which is disclosed in Japanese Utility Model Publication No. Sho 62-41608. In this conventional auto-lock slider, each of front and rear attachment lugs 213, 214 standing on an upper surface of an upper wing 206 of a slider body 201 has a projection 223 on which a cutout 235 in each end of a leaf spring 204 is to be threaded. In assembling, the leaf spring 204 are placed over a locking lever 203 supported by the front and rear attachment lugs 213, 214 in such a manner that the cutouts 235 in opposite ends of the leaf spring 204 are threaded on the corresponding projections 223 of the front and rear attachment lugs 213, 214, and then the leaf spring 204, the front and rear attachment lugs 213, 214, and part of the locking lever 203 are covered by a cover 205 having in its inner wall surface a pair of recesses (not shown) in which the projections 223 are to be fitted.
FIG. 11 shows still another conventional auto-lock slider which is disclosed in Japanese Utility Model Publication No. H4-32973. In this conventional auto-lock slider, a cover 305 has at one end a pair of first projections 313 extending from its inner wall surface and at the other end a second projection 314 having in its top a central V-shape groove. In assembling, one end of the leaf spring 304 is held by inwardly bending the first projections 313 with a cutout 335 of the other end of the leaf spring 304 being threaded on the second projection 314, whereupon the second projection 314 divided at its top by the V-groove is laterally and outwardly bent to hold the sides of the cutout 335. Then the cover 305 is fixedly attached to the upper surface of the slider body 301.
FIG. 12 shows a further conventional auto-lock slider which is disclosed in Japanese Utility Model Publication No. Sho 56-22730, in which front and rear pairs of laterally opposed triangular guide plates 413, 414 stand on the upper surface of a slider body 401 so that a cover 405 can be fitted on the guide plates 413, 415.
According to the first- and second-named prior art publications, the leaf spring 104, 204 is simply placed oil the front and rear attachment lugs 113, 114; 213, 214 on the upper surface of the upper wing 106, 206, whereupon the cover 105, 205 is attached to the front and rear attachment lugs 113, 114; 213, 214 to conceal the leaf spring 104, 204, the front and rear attachment lugs 113, 114: 213, 214 and part of the locking lever 103, 203 on the upper wing 106, 206. In the automatic assembling process, the pull tab 102, 202, the locking lever 103, 203, the leaf spring 104, 204 and the cover 105, 205 are placed successively on the slider body 101, 201 supported on a turn table of an automatic assembling machine, and finally the cover 105, 205, is clenched against the front and rear attachment lugs 113, 114; 213, 214. Since the individual parts are placed on the slider body 101, 201 without being fixed in the automatic assembling process and especially since the leaf spring 104, 204 is placed over the locking lever 103, 203, the leaf spring 104, 204 tends to fall off the locking lever 103, 203 due to the rotation of the turn table so that a high-speed rotation of the turn table cannot be realized, causing only a limited rate of production.
Further, since the leaf spring 104, 204 to be supplied to the automatic assembling machine is assembled as being severed from a continuous length of resilient strip which is originally wound on a spool, the leaf spring 104, 204 is originally warped even after severed so that it cannot be placed over the locking lever 103, 203 in a stable posture due to its warp. Therefore a high-speed operation of the automatic assembling machine cannot be achieved.
According to the third-named prior art publication, the leaf spring 304 is placed in the cover 305 positioned upside down, and then the cover 305 is reversed when attaching to the slider body 301, thus increasing the number of assembling steps so that an increased rate of production cannot be achieved. Accordingly the automatic assembling machine requires a further mechanism in order to reverse the cover 305, which is laborious and time-consuming.
According to the last-named prior art publication, since there exists no part for restricting the lateral displacement of the cover 405 on the slider body 401 in the automatic assembling process even if the cover 405 is supplied onto the slider body 401, it is difficult to position the cover 405 in place so that a quick supply of the cover 405 cannot be achieved. Therefore this conventional slider is not suitable for production by a high-speed automatic assembling machine.